IT'S the stars' favourite food fad, but costly wheat-free products just make most people fatter - with no health benefits at all.

There's one celebrity craze that seems to be taking over the world. Whippet-thin stars including Victoria Beckham, Gwyneth Paltrow and Miley Cyrus all talk about their healthy "wheat-free" lifestyles.

With their enviable figures, it's no wonder thousands of women are following their lead. But giving up bread, pizza, pasta and cakes, which all contain gluten - a gluey protein found in wheat, barley and rye - is not as easy as they make it seem, especially when you don't have a personal chef to whip you up tasty alternatives.

So over the past few years, the food industry, seeing a burgeoning gap in the market, have filled it with an ever-expanding range of "free from" products.

Walk into any supermarket and you'll find at least one aisle stacked with gluten-free foods - everything from fusilli pasta to fruity bars. Even sausages, usually bulked out with breadcrumbs, can be bought by people wanting to avoid gluten.

Of course, for people with coeliac disease, who are physically intolerant to products containing wheat, "free from" options make life a lot easier. But coeliacs can't be the only people buying them. According to the Food Standards Agency, only an estimated 1 per cent of the population is classified as coeliacs - yet this market is growing by 15 per cent every year and is worth $360 million annually. So what's the truth behind the boom?

The study

The authors of a recent paper in the British Medical Journal suggest that the surge in gluten-free living has come about because its products are not only sought by coeliacs, but by people watching their weight.

Ever since low-carbohydrate diets took the nation by storm ten years ago, carbs - which include bread, pasta, potatoes, starchy vegetables and rice - became a dirty word for anyone trying to shed the pounds.

But one ingredient in particular has come in for particular opprobrium. Some experts have claimed it's not carbohydrates as a whole that make some of us pile on the pounds, butcarbohydrates in the form of wheat - and, in particular, the protein called gluten contained within it.

Devotees, including Lady Gaga and Andy Murray, as well as Gwynnie, claim going gluten-free can alleviate everything from tiredness and bloating to spotty skin and hair loss. But are gluten-free products really as good for slimming as we think? Or could they actually be making us fatter, only reducing the size of our bank balances?

Shoppers keen to lose a few kilos may think gluten-free bread will give them a head start when it comes to dieting, but our investigation reveals the reverse could be true.

When manufacturers create a gluten-free product, they remove the wheat protein from the food by swapping wheat flour for another flour such as almond, rice, corn or even bean. However, this missing gluten makes it difficult for breads and bakery products to retain their shape and softness as they cook.

To alleviate this, additives (such as xanthum gum and hydroxypropyl methylcellulose) or corn starch are introduced. Extra sugar and fat are also added to the products to make them tastier. The result is that gluten-free bread can actually add pounds to your waistline.

Sarah Sleet, from Coeliac UK, agrees that, on the whole, "gluten-free fresh breads are higher in fat compared with breads containing gluten. This is largely because saturated fats are needed to make gluten-free bread soft".

She cautions that it's a myth to think that you'll lose weight by eating them.

"Going gluten-free does not necessarily make you healthier or lose weight," she says. "A gluten-free muffin or a normal muffin is still a muffin. It's still high in fat."

The subjects

The fattening side-effects of eating gluten-free products are familiar to 44-year-old Jo Smith, who runs a vintage clothing shop and lives with her artist partner Michael. She has put on 12 kilograms since going gluten-free.

"I went to the doctor about bloating and stomach pains ten years ago," she says. "They diagnosed IBS and didn't test for coeliac's disease - there just wasn't the awareness of the condition that there is today.

"I knew it was wheat causing my problems after I was left doubled over with pain one day when I"d eaten nothing but two sandwiches. From then, I stopped eating anything with wheat in it.

"But I'm living proof that going gluten-free won't help you lose weight. I've put on two stone (12kg) since coming off gluten - I used to be a small size eight to ten and now I'm a 12 to 14.

"Weight gain doesn't concern me, as even though I haven't been tested, I believe wheat was poisoning me. But it baffles me that someone who has no medical need to go gluten-free would choose to do so."

Claire Combes, 44, also piled on the pounds after going gluten-free.

"Five years ago, I found that when I ate food high in gluten, such as bread, pasta and potatoes, I felt bloated and tired," says Claire

"I wasn't overweight, but decided I'd switch to gluten-free products to see if this improved my health. I stocked up on gluten-free bread, spaghetti and pasta, as well as gluten-free snacks such as crisps and biscuits.

"These products were more expensive, but I felt they were worth it for their health benefits. I didn't have a clue they were higher in fats, and I had no idea they could make me put on weight, rather than lose it. Over the next few years, as I stuck to my gluten-free regime, my weight rose to 9 st 10 lb (63 kilograms).

"I couldn't understand it - I thought I was doing everything right; watching what I ate and eating a gluten-free diet. I also did Pilates and walked everywhere.

"Then I discovered from a friend that eating a gluten or wheat-free diet does not automatically make you slimmer. She recommended a more balanced and nutritious diet with more fresh food and veg.

"Following this, I have managed to drop to 8st 3lb (52 kilograms). I avoid any sort of bread - gluten-free or otherwise - and pasta."

As Claire points out, the other side of the free-from fad is that it's a money-spinner for food companies. Gluten-free products sell for a premium price.

The companies' justification for this is that demand is lower, making the cost of the materials and overheads for the products higher. There's also the expense involved in avoiding any cross-contamination with gluten, meaning that manufacturers usually need to set up dedicated factories and have specialist equipment.

The boom

So, if going gluten-free won't make us thinner or healthier, why are people adopting it in their thousands?

Books such as the New York Times bestseller Wheat Belly by William Davis could be part of the reason. Davis, a cardiologist, links our consumption of wheat to everything from schizophrenia to dandruff, diabetes and arthritis. He believes wheat is a "chronic poison" and even says it's as dangerous as heroin.

It all sounds a bit far-fetched - after all, the Western diet has included wholegrains since biblical times. Dr Davis, however, claims that much of the wheat found in our bread today is different to the type eaten by our grandparents.

Fifty years ago, scientists made a strain of "dwarf" wheat that grows twice as fast and is twice as hardy as traditional wheat. This variety is higher in gluten and, according to Dr Davis and other experts, is highly addictive - a claim rubbished by other nutritionists.

One of them is Ian Marber, who is deeply sceptical of the notion that wheat is bad for us. "The reason the vast majority of people think they feel better on a gluten-free diet is because they're suddenly making better choices.

"They are thinking about what they eat, reducing their overall carbo-hydrate intake and not going to fast-food restaurants.

"Obviously, you can do that without avoiding gluten. Selling this myth that gluten is as addictive as heroin or that it's this terrible poison simply treats people like idiots.

"I know of no biochemical evidence to support this. The problem is not that wheat is in some way flawed - it's that we eat too much of it. Our diet has become too carbohydrate-heavy. But cutting out wheat is not the panacea people think it is. Wheat has a bad reputation, but it's an important source of B vitamins, fibre and calcium."

What's more, as a coeliac, Ian says: "I find it strange that people might be following guidelines for a disease they don't have. The prevalence of food intolerances among the general public is criminally over-estimated.

"People eat a huge bowl of pasta, feel uncomfortable and then decide they are allergic. They're not - they've just eaten too much."

Of course, going gluten-free may appeal to dieters as a way of shifting the blame for their bad health. It's far easier to believe you have a medical problem than admit to yourself it's your fault you"re overweight. The irony is the "cure" to their perceived problem could be bad for them.

A study published in the Journal of the Academy of Nutrition and Dietetics last year concluded: "There is no evidence to suggest following a gluten-free diet has any significant benefits in the general population.

"Indeed, there is some evidence to suggest that a gluten-free diet may adversely affect gut health in those without coeliac disease or gluten sensitivity."

Perhaps the answer lies in finding the middle ground. If you're eating Weetbix for breakfast, a baguette for lunch and pizza for dinner, it's probably time to cut down and introduce more fruit and vegetables - but be aware that going gluten-free may not be the answer to your wellbeing or your waistline.

As Ian Marber says: "It's immoral that this industry has sprung up that is effectively selling us an illness most people don't suffer from.

"Going gluten-free has become an obsession that is denying people the real pleasure to be found in food."

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